The invention relates to a device and a method for the controlled damping of the body movement as well as the wheel movement of a vehicle as a function of its dynamic driving situation.
In such a case, by preselecting different comfort and damping modes, the driver of the vehicle should especially be able to cause the vehicle, for example, in the “comfort mode”, to have a soft comfortable damping of the vehicle body with respect to the vehicle wheels, while, in the case of a “standard” adjustment, a normal damping will be present. And, in a “sporty” mode, a hard to extremely hard damping will be provided. The different damping is carried out particularly by way of controlled adjusting damper systems arranged between the vehicle body and the wheels.
Such a control of the damping of a vehicle as a function of different preselected comfort modes is known from German Patent document 100 33 770 A1. Furthermore, reference is made to German Patent document DE 42 12 852 A1, which describes a wheel suspension system of a motor vehicle with a damping controlled as a function of the dynamic driving situation and of the loading condition of the vehicle.
Such systems change the damping particularly depending on the driving situation of the vehicle and thereby provide a particularly high comfort level while high dynamics of vehicle handling are simultaneously preserved. Known devices for the controlled changing of the damping of a vehicle operate by using a fixed set of parameters which covers all dynamic driving situations.
In particular, in the case of vehicles cushioned by steel springs in connection with a high load, the very high definition of comfort may then result in the occurrence of a “bottoming” of the wheels. This means that the damping is not sufficient, that instead the entire spring travel is used up and that the wheel suspension strikes hard against the vehicle body. On the one hand, this can be felt and heard by the vehicle occupants and clearly reduces comfort. On the other hand, the bottoming may also lead to damage to the participating components.
This problem can be remedied if, besides depending on the dynamic driving situation as such, additionally the loading of the vehicle is taken into account when adjusting or controlling the damping. In this sense, the above-mentioned German Patent document DE 42 12 852 A1 describes a vehicle in the case of which so-called characteristic damping force values are changed by several steps from a soft to a hard adjustment if the loading capacity of the vehicle exceeds a predefined value. However, this basically known approach cannot simply be taken over for existing control concepts with a damping that is variable as a function of the dynamic driving situation because this would result in a significant limitation of the variable damping that, as desired, is adapted as finely as possible for different dynamic driving situations.
It is therefore an object of the invention to provide a device and a method for the automatically controlled or controlled damping of a vehicle, in the case of which also at a high or different loading of the vehicle, a comfortable damping in all conditions of driving dynamics will be ensured in a favorable manner.
According to the invention, this and other objects are achieved by a device and method for the controlled damping of a vehicle, having a storage unit for storing a set of controller parameters R1 to Rn for controlling the damping of the unloaded vehicle as a function of its dynamic driving situation 1 to n, a detecting unit for detecting a loading condition b of the vehicle, an adaptation unit for adapting the set of controller parameters R1 to Rn as a function of the detected loading condition b to a set of controller parameters R1b to Rnb, and a damper for damping the vehicle as a function of the set of controller parameters R1b to Rnb as a function of its dynamic driving situation 1 to n. The storage unit is adjusted for storing at least two sets of controller parameters R1k1 to Rnk1 and R1k2 to Rnk2 for different comfort modes k1, k2 of the unloaded vehicle, and is adjusted either for storing for each set a set of controller parameters R1Bk1 to RnBk1 and R1Bk2 to RnBk2 for the fully loaded vehicle or a single set of controller parameters R1B to RnB for the fully loaded vehicle. Furthermore, the adaptation unit is adjusted for determining the set of controller parameters R1b to Rnb by a selection of the comfort mode and a mathematical interpolation between the thereby selected set of controller parameters for the unloaded vehicle and the pertaining or single set of controller parameters for the fully loaded vehicle.
In the present case, a device for the controlled damping of a vehicle is provided which comprises a storage unit for storing a set of controller parameters R1 to Rn for controlling the damping of the unloaded vehicle as a function of its dynamic driving situation 1 to n (in which case n is a natural number greater than 1), a detecting unit for detecting a loading condition b of the vehicle, an adaptation unit for adapting the set of controller parameters R1 to Rn as a function of the detected loading condition b to a set of controller parameters R1b to Rnb, and a damper for damping the vehicle as a function of the set of controller parameters R1b to Rnb as a function of its dynamic driving situation 1 to n.
It was recognized that a very large number of possible influence factors would always have to be taken into account when damping a vehicle. In addition to the actual dynamic driving situation, such influence factors are, for example, a driving speed not appropriate for the base surface, the wind pressure at the vehicle, different tire pressures, the driver's steering behavior and much more. Although it would be technically feasible to take all theses factors into account, in view of the costs, the resulting product would not be marketable. In contrast, according to the invention, the loading condition of the vehicle was selected as the single additional factor that is taken into account for the damping of the vehicle in addition to the dynamic driving situation. In this manner, the solution according to the invention creates in a cost-effective and simultaneously considerably more comfortable damping. The invention thereby additionally utilizes the technique of and the experience with existing systems in that the starting point is the currently used set of controller parameters R1 to Rn for the unloaded vehicle. This set of controller parameters is only changed in the direction of a detected loading condition of the vehicle. Systems existing at the vehicle can be advantageously used also for detecting the loading condition. Particularly in the case of steel-spring-cushioned vehicles, level sensors and, in the case of air-suspended vehicles, pressure sensors are advantageously queried, or a combination of such test signals is analyzed. It is an advantage that, as a rule, at least the level sensors in the corresponding vehicles are part of the standard equipment, so that no additional costs will arise.
In a first embodiment of the device according to the invention, the storage unit is adjusted for storing at least two sets of controller parameters R1k1 to Rnk1 and R1k2 to Rnk2 for different comfort modes k1, k2 of the unloaded vehicle, and adjusted for storing for each set a set of controller parameters R1Bk1 to RnBk1 and R1Bk2 to RnBk2 for the fully loaded vehicle, and the adaptation unit is adjusted for determining the set of controller parameters R1b to Rnb by means of a selection of the comfort mode and a mathematical interpolation between the thereby selected set of controller parameters for the unloaded vehicle and the pertaining set of controller parameters for the fully loaded vehicle.
By way of this first embodiment, a functionally optimal solution is created which, however, still requires comparatively high expenditures with respect to data handling, thus the storage and processing of the stored data. In the case of this approach, the sets of controller parameters are doubled, one parameter set being provided for the unloaded and one parameter set being provided for the loaded vehicle condition. The parameter set used for the actual controlling is calculated from these two sets while taking the actual loading condition into account. A storing of intermediately stored data sets requiring much higher expenditures is thereby eliminated. In particular, an adjustable, partly linear interpolation is used as the calculating method.
In a second embodiment of the device according to the invention, the storage unit is adjusted for storing at least two sets of controller parameters R1k1 to Rnk1 and R1k2 to Rnk2 for different comfort modes k1, k2 of the unloaded vehicle, and adjusted for storing a single set of controller parameters R1B to RnB for the fully loaded vehicle, and the adaptation unit is adjusted for determining the set of controller parameters R1b to Rnb by means of a selection of the comfort mode and a mathematical interpolation between the thereby selected set of controller parameters for the unloaded vehicle and the single set of controller parameters for the fully loaded vehicle.
By way of this second embodiment, the required storage space can be further reduced. Furthermore, the pertaining damping system can be coordinated more easily with the only one parameter set for the fully loaded condition. A coordination with three different modes for the fully loaded condition is, however, eliminated. This embodiment nevertheless meets the requirements of “preventing a bottoming” and of “increasing the driving comfort.” Low application expenditures and a storage-space-saving presentation justify the possibly resulting compromises with respect to the achieved driving comfort.
For the further reduction of the required storage space, in the case of the device according to the invention, the storage unit is adjusted for storing at least two sets of controller parameters R1k1 to Rnk1 and R1k2 to Rnk2 for different comfort modes k1, k2 of the unloaded vehicle, of which one set is designed for a maximally hard damping of the vehicle, and the adaptation unit is adjusted for determining the set of controller parameters R1b to Rnb by means of a selection of the comfort mode and a mathematical interpolation between the thereby selected set of controller parameters for the unloaded vehicle and the set of controller parameters for the maximally hard damping of the vehicle.
This further development is based on the circumstance that, in the case of relevant vehicles, a maximally hard damping is designed in the “sporty” mode in which, if possible, no “bottoming” will occur even if the vehicle is fully loaded. This type of design of the maximally hard damping is now, according to the invention, utilized as a maximal parameter set also for the remaining comfort modes, such as “comfort” and “standard” with regard to a fully loaded vehicle in these modes. Therefore, no separately generated parameter set for the “fully loaded vehicle” condition is necessary in the memory.
In an advantageous further development of the device according to the invention, an intensified basic damping of the vehicle is taken into account with each set of controller parameters for the fully loaded vehicle.
This further development is based on a derivation from the active physical chain as the loading of a vehicle increases. The additional loading results in a displacement of the center of gravity and in an increase in mass, to which a reaction according to the invention takes place, as explained above.
In an additional advantageous further development of the device according to the invention, an increased damping against a lifting, pitching and/or rolling of the vehicle is taken into account with each set of controller parameters for the fully loaded vehicle. Such an adjustment of the controller parameters acts especially against the increase in mass at the vehicle when the latter is loaded.
In yet another advantageous further development of the device according to the invention, an increased damping of the rearward structure of the vehicle is taken into account with each set of controller parameters for the fully loaded vehicle. This further development is based on the recognition that, with an additional load, in the case of known vehicles, as a rule, their center of gravity is displaced toward the rear and, as a result, the distribution of the weight to the front and the rear axle also changes.
According to the invention, this object is further achieved correspondingly by a method for the controlled damping of a vehicle. The further developments explained for the device also exist analogously for this method.
By means of the solution according to the invention and its further developments, a “bottoming” of the wheels can be prevented or at least reduced or lessened in all operating conditions of a vehicle. Particularly in the case of vehicles without a level control system, the vibration comfort is considerably increased in a cost-effective manner. Damage to components, such as axles, springs, dampers as well as their connection to the vehicle body, can be reduced. The service life of such components is thereby lengthened. Finally, the manufacturing costs of pertaining axle systems, as a whole, can also be reduced because the components can be constructed in such a manner that a lower collective load is adhered to.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.